1. Field of the Invention
This invention relates generally to an apparatus and method for use in removing and replacing used coolant in the cooling system of a vehicle, and more specifically, this invention relates to an apparatus and method for changing the antifreeze in an automobile cooling system by use of a garden hose.
2. Description of the Prior Art
Vehicle manufacturers typically advise owners of their vehicles to change the antifreeze in the cooling systems of those vehicles every two years, in order to prevent the accumulation of corrosion materials, such as rust and solder corrosion residue. The corrosion materials are formed as the corrosion inhibitors in antifreeze break down from heat over time. These corrosion materials reduce cooling system efficiency by interfering with the flow of coolant through the air/liquid heat exchanging fin-tubes of the radiator core. An effective cooling system is not only important for engine performance and life, but in many automobiles the transmission fluid is also cooled by circulation through the radiator Further, the abrasive nature of the suspended corrosive materials increases the wear on water pump, hoses, thermostat, and heater core--and malfunction of cooling system components is said to be the number one cause of highway breakdowns.
Accordingly, there are certainly good reasons why the vehicle makers' recommendation that the old coolant be flushed out and replaced with fresh coolant every two years should be followed. However, industry data indicates that most (about 78%) of the antifreeze sold every year is sold to do-it-yourselfers. And, only 30% of these buyers say that they change their antifreeze regularly, instead of just adding more when needed. Moreover, it is likely that many within this 30% who say that they change their antifreeze are, in fact, only removing the old coolant and corrosion materials from the radiator, and not from the whole system.
To properly change the coolant in a vehicle cooling system, it is not only necessary to drain and flush out the radiator (which normally contains 40% to 50% of the coolant in the system), but it is also necessary to drain and flush out the engine block, heater core and connecting hoses, since the remainder of the coolant is in those areas. Draining and flushing of the radiator does not drain or flush the coolant from the engine block, heater and the connecting hoses, because the flow of coolant from the latter areas to the radiator is blocked by the thermostat, which is closed unless the system is at operating temperature. Opening up a cooling system which is closed and at operating temperature is not advisable because, in this state, the system is pressurized and opening it may result in hot coolant being sprayed on the operator. Thus, coolant changes should begin only with cold systems, when the system is not pressurized, the thermostat is closed, and the flow of coolant from engine, heater and hoses to the radiator is blocked. As a result, those car owners who prudently start with a cold system and drain just the radiator are removing only the 40% to 50% of used coolant and suspended corrosion which is contained in the radiator, leaving the remainder in the rest of the system.
There are presently three general approaches an individual vehicle owner may follow to drain and flush old coolant and corrosion from the entire cooling system--not just the radiator. All have their drawbacks.
Consider first the continuous flushing technique utilized by some professional equipment, and some kits sold for do-it-yourself use [an example is a kit sold by First Brands Corporation (PRESTONE) under its trademark "FLUSH 'N FILL"]. With this technique, a sealed connection must be made by installing a garden hose-coupled inlet tee ("T") in the cooling system. This is accomplished by cutting into a heater hose and installing the inlet "T" between the severed hose ends. With the radiator drain cock open, the radiator cap off, and the engine running (to keep the thermostat open), water is continuously admitted through the inlet "T" and circulated by the water pump, displacing old coolant which discharges through the radiator drain and the radiator cap neck. After a sufficient period of time, drainage clarity indicates that old coolant and corrosion have been displaced by clean water.
For a person who is not a mechanic, utilizing this continuous flushing approach presents a number of problems:
(1) Installing the inlet "T" requires that the correct hose and installation point be identified, that the reinforced hose be cut and that the "T" be properly installed so that it does not leak (the FLUSH 'N FILL instructions recommend consulting a qualified mechanic if unsure). PA1 (2) The approach generates a relatively large volume of waste liquid (up to 700% of cooling system capacity) flowing from both the radiator neck and the drain. This waste liquid is difficult to contain and usually is left to splash on the vehicle and the ground. Since antifreeze is composed largely of ethylene glycol, which is harmful or fatal if swallowed and is poisonous to animals, this method creates a hazardous environmental condition. PA1 (3) The drain cock on the radiator must be opened and closed, respectively, before and after the operation. PA1 (1) Either opening the drain cock or removing the bottom hose frequently requires the operator to get under the car, because there is insufficient room in the engine compartment: to pull hard enough on the bottom hose to remove it from the radiator mounting tube without damaging it or causing injury; or to use a wrench on the drain cock handle, which is intended for hand turning but frequently is stuck so tight by corrosion that it requires a wrench. Many automobiles do not have sufficient clearance to permit the operator to perform either of these operations without jacking up the car, with the attendant danger. PA1 (2) Use of a wrench on the handle of a drain cock stuck by corrosion involves a substantial risk of breakage, requiring either a difficult replacement of the drain cock or the more expensive replacement of the entire radiator. PA1 (3) Even with the retaining clamp removed, radiator hoses frequently adhere so tenaciously to the radiator hose mounting tube (which, like the radiator itself, is made of light gauge, soft metal), that it is necessary to either cut the hose off the tube or to use a screwdriver or pry bar to push the hose off the tube. If cut, the hose must be replaced, and either cutting or prying the hose risks damage to the mounting tube itself, which again could result in the need to replace the radiator. PA1 (4) Immediately upon opening the drain cock or hose, used coolant flows out, frequently resulting in both the operator and the ground being covered by the used coolant before a receptacle can be used to collect it. PA1 (1) Engine drain cocks are generally even more difficult to access through the engine compartment than radiator drain cocks, and they more frequently require the operator to jack-up and get under the car to open and close them. PA1 (2) Removal of the thermostat requires: unbolting a housing from the engine block; prying the thermostat loose from its gasket and sealant without damaging it; scraping the mounting surface clean; and replacing the thermostat gasket and sealant upon re-mounting of the thermostat. PA1 (3) Removal of heater hoses presents the same type of difficulties encountered in removing engine-to-radiator hoses, and replacement of the two heater hoses (which are very similar in appearance) in their proper locations is an added problem. PA1 (4) With the system open at many points for flushing purposes, it is difficult to collect the waste and flush water exiting these many openings when flush water is injected. PA1 (1) providing a conduit suitable for both extracting used coolant and injecting replacement water through the radiator cap opening as the only interface with the cooling system, thus requiring that only the radiator cap, and not the drain cocks or hoses, be opened; PA1 (2) not requiring any sealed connection to the cooling system, so that the only contact of the operator with the cooling system is the unsealed insertion of the conduit through the radiator cap opening; PA1 (3) providing a control device which is simple to understand and operate to achieve the desired result; PA1 (4) making it safe for the operator to repeat the draining and refilling of the radiator, even when the system is at operating temperature, rather than waiting for the system to cool down; PA1 (5) minimizing and fully containing used coolant and flush water for proper disposal; and PA1 (6) requiring, as additional equipment, only a garden hose connected to a faucet or other source of water under pressure, and a common household bucket.
Professional flushing equipment designed to contain waste coolant and flush liquid requires at least one additional sealed connection to be made to the cooling system, for purposes of conveying waste liquid out as flushing liquid is pumped into the system. This, of course, adds to both the cost and complexity of use of such systems.
A second method which may be used involves opening up the system at multiple points. With this approach the thermostat, heater hose and the lower engine-to-radiator hose are removed, and the drain cocks on the engine and the radiator are opened. It is then possible to flush water through the various parts of the system without the need to install a permanent inlet "T" or run the engine to keep the thermostat open. However, there are also problems with this approach.
Consider first the draining of old coolant and flush water from the radiator. The radiator can be drained by either opening the drain cock located on the engine side of the radiator near the bottom or by removing the bottom radiator to-engine hose, which is also located on the engine side of the radiator near the bottom of the radiator. (For complete flushing, the drain cock would be opened and the hose would be removed.) For a person who is not a mechanic, performing this seemingly simple task involves a number of practical difficulties:
Draining coolant and flush water from the engine block, the heater and the connecting hoses is an even greater problem:
The third method of draining and flushing the entire cooling system involves repeatedly draining the radiator, refilling it with water, and running the engine to normal operating temperature. This causes the thermostat to open and permits the coolant previously trapped in the engine, heater and hoses to mix with the clean water added to the radiator. Because in a typical cooling system the water pump has the capacity to turn over many times the total system capacity every minute, and the thermostat, when open, will likewise permit many times the system capacity to circulate to the radiator each minute, the fresh water is quickly and thoroughly mixed with remaining used coolant.
By repeating the sequence of steps, the amount of old coolant and corrosion remaining in the system can be reduced by approximately one-half each time the radiator is emptied. Thus, the first time the radiator is emptied, approximately one-half of the used coolant in the system is removed. After running the engine to mix the remaining used coolant with the fresh water, draining of the radiator reduces the remaining used coolant to one-quarter of that initially contained in the the cooling system. The third repetition reduces it to one-eighth; the fourth to one-sixteenth, etc.
In this way, the operator can flush a high percentage of the total old coolant and corrosion from his entire cooling system (not just the radiator) without the need to open drain cocks or hose connections on the engine. While mechanically simpler, however, this method nevertheless requires a great deal of physical labor. The operator must get under the automobile several times to open and close the radiator drain cock, or to remove and replace the bottom radiator-to-engine hose, whichever draining procedure is being used. Also, if the car had to be jacked up to take these actions, it would have to be let down each time in order to run the engine. Thus, for example, to flush at least 87.5% of the old coolant from the system requires that the radiator be drained three times, which would require that the operator get under the automobile six times (three times to open the draining point and three more times to close the draining point). Further, after the first engine warm-up to open the thermostat, the operator would either have to open the draining point on a hot radiator or wait some period of time for the system to cool down before proceeding.
Although a pump could be utilized to drain the radiator, in order to avoid the need to repeatedly open and close the drain cock, most automobile owners could not justify the cost of such a pump, nor would they be willing to undertake the storage and maintenance of such a pump.
Accordingly, while there are clearly good reasons to flush out and recharge cooling systems in accordance with the vehicle maker's recommendations, many car owners do not do so because of the attendant difficulty of the task. Therefore, there are a great number of vehicles that are not serviced as they should be, with the associated high costs of: (1) poorer performance and more frequent maintenance; (2) shortened engine life; and (3) more frequent highway break down. Such costs could be reduced by providing a way for individual vehicle owners to properly flush their cooling systems and recharge them with fresh antifreeze, without the need of substantial mechanical expertise and physical labor, or the need to acquire expensive pumping equipment.